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72 454 header install problems

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Old Apr 17, 2025 | 06:43 PM
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Default 72 454 header install problems

Recently got my Hedman (p/n 68090 via McJacks Corvettes) headers. Is it easier to install them from the top or bottom on the driver side? It appears the OEM steering box is all up in my way. I'm not sure I can lift the car high enough to get under it to rotate the header into position.

The passenger side is probably not going to work. The mid pipe curls up to mate to the factory exhaust manifold and I already see the header collector makes a horizontal turn at the collector and is not the right angle to bolt up to the midpipe like they supposedly able to.

Has anyone wrestled with these specific headers before?

On the bright side the OEM exhaust manifolds came right out and not one bolt snapped off in the head!
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Old Apr 17, 2025 | 07:25 PM
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Can't help with that but it be a good time to check/replace spark plugs.
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Old Apr 17, 2025 | 07:28 PM
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Yeah I already got a new set of plugs on the way. I noticed the back plugs had some weird green crap on the tip (AC Delco copper plugs R45TS)
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Old Apr 17, 2025 | 08:11 PM
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Headers that hook up to the factory mid pipes? Never heard of such a thing.
Drivers side, clutch linkage and steering box. I would come up from underneath. If that means your car needs to be higher, then get it on a lift. That's what friends are for!
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Old Apr 17, 2025 | 10:27 PM
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I always did mine passenger side from the top and raise the car high and go from the bottom on the driver's side. The Z/bar has to come out. It's a tight fit
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Old Apr 18, 2025 | 09:48 AM
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I have a set of the 68090 headers. my car is a 71 auto w/pwr brakes but no power steering. they go in from the bottom. needed some slight clearancing for the steering box on the captains side and idler arm bolts on the drinkers side but otherwise no major problem. I do not see any way they would go in from the top but I could be wrong. the heddmans are the black headers. you can see where i had to "massage" the #3 tube to get it past the steering box. some have installed these with no issues. every car is different. the white coated headers are blackjacks that i have had since the 80's and still on the car. back in the early 90's when i put a set of merlin oval port heads on the car i had to clearance the heck out of them on the captains side. the merlins had raised exhaust ports. with the 496 and race rite heads i have in the car now there is plenty of room for the blackjacks but i had to do a little work on the heddmans as you see in the picture. once i get the heddmans coated i will be putting them in the car.
Pat


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Old Apr 18, 2025 | 01:19 PM
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Good luck.
I attempted to install several different headers on my 73 454 project a while back and ran into several fitment issues.
Both Hedmans and Hookers will need modifications to the primary tubes to make them fit.

I found the only headers that fit without modifications were Sanderson short tube headers.

What you describe sounds more like you are installing short tube headers because that’s what McJacks makes and they are supposed to bolt up to the oem mid pipes.

Are you installing short tube or long tube headers?

Either way, with the body on the car, you will need to install them from the bottom and if you’re installing long tube headers, they will need to be modified before you’ll be able to get them up and in.

This is a thread that I did trying to fit headers on my big block.
https://www.corvetteforum.com/forums...hlight=Headers


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Old Apr 18, 2025 | 10:20 PM
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After much cussing I wrestled the driver side header into position from underneath the car. The solution is dropping the midpipe down and cutting the upward bend off it. The header kit came with some extensions to remake the connection to the midpipe. Unfortunately it did not come with clamps to secure the pipes. Its not a big deal because I plan on swapping the factory midpipes and mufflers for something better..The current setup is raggedy from bottoming out not to mention the narrowed areas were the pipe bender necked the pipe down.

The new problem is that some of the header bolts will not thread all the way in. I suspect the threads in the head may have corrosion in them. I cleaned them with brake cleaner and compressed air but something still isn't right. As soon as I find my tiny camera to connect to my phone I shall see. Also rounded off one of the new bolts. 12 point bolts are the drizzling ***** I hate them. New 6 point bolts incoming soon. The factory bolts have too fat of a head on them to clear the 2" primary so I can't use them.

The good news is that the fitment is damn near perfect. No ball peen hammer massaging was required.

I may attempt the passenger side tomorrow.
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Old Apr 19, 2025 | 07:44 AM
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When I put headers on my 427 I had to make a set of pipes that connected the headers to the chambered exhaust system. It was not that hard to do and it sealed up nicely.

The Hedman Headers were a straight-in, easy installation on my 1968 427. My engine has power steering, power brakes and a Power pedal so there was not much in the way, down below in the engine compartment. I put the headers on and never had to touch them for close to 30 years. The bolts never got loose or anything. The Hedman Headers are of great quality and they fit right on the engine with out any modifications.

After decades of reading and hearing about the header bolts getting loose and leaking, my Hedmann Headers have been very "boring".

No matter which headers that you end up choosing, I would strongly recommend using a Soft Aluminum Header Gasket between your cylinder head and the header flange. These gaskets are the best way to seal an exhaust system because they are soft and flexible allowing them to seal to Ir-regularities on the surfaces.
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